Residual chlorine electrode

Other methods for the determination of chlorine in seawater or saline waters are based on the use of barbituric acid [13] and on the use of residual chlorine electrodes [ 14] or amperometric membrane probes [15,16]. In the barbituric acid method [12], chlorine reacts rapidly in the presence of bromide and has completely disappeared after 1 minute. This result, which was verified in the range pH 7.5-9.4, proves the absence of free chlorine in seawater. A study of the colorimetric deterioration of free halogens by the diethylparaphenylene-diamine technique shows that the titration curve of the compound obtained is more like the bromine curve than that of chlorine. The author suggests... 

Model 97-70 electrode from Orion Research, an electrode for residual chlorine [321 ], is based on a cell consisting of a platinum electrode which reacts to the I2 /I" system, and an iodide ISE. The EMF of this cell is given by the relationship... 

The first is that the oxidation mechanism of organics in WEO occurs directly at the electrode surface, without evolving intermediate reactions that form chlorinated compounds, and that can be supported by the fact that free residual chlorine is not detected in the effluent samples for all electrolysis conducted at temperatures higher... 

TOTAL RESIDUAL CHLORINE BY ION-SELECTIVE ELECTRODE FROM BENCH TOP TO CONTINUOUS MONITOR... 

Measurement of total residual chlorine by ion-selective electrode is dependent upon the reaction ... 

Environmental and Safety f actors. The primary environmental concern for the coaling plant is actually the residual material on the anode structures being returned for recoating. Therefore the anode user must enact effective cleaning procedures prior to shipment. Overall, the DSA [Electrode Corp.) has made chlorine manufacture cleaner, more consistent, simpler, and therefore safer. 

It has been already said that the back electromotive force makes up for the electrolyzing voltage, as long as E < Ev. This is, however, not exactly expressed as actually some current flows through the system even before the decomposition voltage Ep is reached (see Fig. 16, line OB). This small current, called residual current, is caused by the fact that the products of electrolysis (chlorine and hydrogen) do not permanently remain in the electrodes, as theoretically assumed, but a small quantity is lost by dissolution in the surrounding electrolyte and by diffusion into the bulk of electrolyte. Those losses are compensated by the residual current. 

The product contains (besides some residual F and H) also inserted NBU4 , i.e. it is naturally n-doped. Even in the absence of BuOH, reactive nucleophiles like [(CH3)2NCHO] or (CH3)2N can be generated by preelectrolysis of dimethylformamide solutions [59]. Such a process allows electrochemical deposition of diamond-like carbon on an aluminum electrode [78] and it also produces polyyne from PVDF (cf. Eq. 4.22a). At similar conditions, PTFE shows no reactivity [59] and polyvinylchloride is dehydrohalogenated only to polyacetylene [79-82]. However, Zra 5-poly-acetylene, which was stereoregularly chlorinated by FeCh, is carbonizable by electrochemically generated BuO (cf. reactions 4.22 and 4.22a) [83] ... 

Finally, we consider the membrane cells in Fig. 6.5. The electrode processes are the same as those in the diaphragm cells (Eqs. 1 and 2). Anolyte processing is quite similar to that practiced with mercury cells. We saw above in the discussion on brine treatment that membrane cells had stricter requirements. The same is true regarding dechlorination of the depleted brine. After vacuum dechlorination, the residual active chlorine content is high enough to damage the ion-exchange resin in the brine purification... 

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